Noise properties of a resonance-type spin-torque microwave detector

We analyze performance of a resonance-type spin-torque microwave detector (STMD) in the presence of noise and reveal two distinct regimes of STMD operation. In the high-frequency regime, the minimum detectable microwave power P-min limited by the low-frequency Johnson-Nyquist noise and the signal-to-noise ratio (SNR) of STMD is proportional to the input microwave power P-RF. In the low-frequency regime, P-min is limited by the magnetic noise, and the SNR is proportional to root P-RF. The developed formalism can be used for the optimization of the practical noise-handling parameters of a STMD. (C) 2011 American Institute of Physics. [doi :10.1063/1.3612917]